As a backyard pool owner, you should check the disinfectant (chlorine or bromine) level and pH at least twice per day (and more often when the pool is in heavy use) to make sure they are correct: 1–10 parts per million (ppm) free chlorine or 3–8 ppm bromine. pH 7.2–7.8.
Pools are Fun!
Dip the bacteria test strip into a vial containing 6 drops of your pool water, and in 10 minutes the results are plain to see. It's that easy. Make it a habit for good health—keep a supply on hand to test the safety of your pool.
The CDC recommends a free chlorine level of 1 ppm for your pool and 3 ppm for your hot tub. But, the pH of your pool matters, too. Chlorine only works well if the pH of your pool falls within the right range. If the pH of your pool is too high (above 8), chlorine is much less effective at killing germs.
It takes about 24 hours for the chemicals to properly circulate in order to get an effective reading from the retest. The water test will assess the pH, chlorine, total alkalinity and calcium hardness. If you use chlorine in the pool, you should also test for cyanuric acid.
Use a filter cleaner, or change the sand or cartridge if it's not been done in many years. Use clarifier to help coagulate suspended particles or use flocculant to drop particles to the bottom. Fill the pool high with water and vacuum the pool to waste, by setting a multiport filter valve to waste (sand or DE filters).
Pool water turns green because of algae in the water. Algae can grow rapidly, particularly when it's warm like Summer, which is why it can surprise you overnight. This generally comes down to an imbalance or lack of chlorine in the water.
Poor Filtration
If dirt is reappearing at the bottom of your swimming pool after you've vacuumed it your pool's filter may be working poorly. Pool filters often work poorly because they're in need of cleaning. If you have a sand filter for your pool you need to make sure that the sand is sharp and freshened up.
If there has been a serious invasion of excess dirt and debris, you may also need to shock your pool. Vacuuming is recognized as the only way to remove sediment from the bottom of a pool.
Since brown algae is extremely chlorine-resistant, several other chemicals such as shock and an algaecide specifically designed for mustard algae will help get rid of the infestation. This will often result in cloudy pool water, so use clarifier to correct this problem.
If ground water is not a problem a pool can be left empty for weeks or even months as long the hydrostatic relief in the bottom of the pool is open and functioning. If the time frame of the pool being empty gets into freezing weather there is real risk of freeze-thaw damage to surface of the pool.
Should the green be due to pollen, there may be little to do in the way of minimizing the discoloration short of erecting a building around the pool. Fortunately, assuming there are no allergies to the pollen, it is safe to swim in a pool with that as the cause for green water.
Chlorine, either solid or liquid, is a pesticide used in pools to destroy germs, including those from feces, urine, saliva and other substances. But excessive exposure to chlorine can cause sickness and injuries, including rashes, coughing, nose or throat pain, eye irritation and bouts of asthma, health experts warn.
TEST IN THE MORNING
If you are having chlorine issues in your pool, the best time to get a water sample is in the morning. Even with proper amounts of chlorine stabilizer, chlorine will burn-off during the day. Testing in the morning will give your water a chance to circulate all night and avoid the sun's UV rays.
If the chemicals used to kill germs (chlorine or bromine) in pools, hot tubs, and water playgrounds are not kept at the right level, these germs can multiply and make swimmers sick.
Germs like crypto, E. coli, and giardia are spread in public pools where chlorine and pH levels are too low. Symptoms of all three illnesses include diarrhea, weight loss, nausea, vomiting, dehydration, and stomach cramps.
Crypto is the most common cause of diarrheal illness and outbreaks linked to swimming pools or water playgrounds because it is not easily killed by chlorine and can survive up to 10 days in properly treated water.